Process and composition of matter for deoxidizing metals and alloys



Patented Nov. 24, 1925.

UNITED STATES PATENT OFFICE.

ALADAR PACZ, OF CLEVELAND HEIGHTS, OHIO.

PROCESS AND COMPOSITION OF MATTER FOR DEOXIDIZING METALS AND ALLOYS.

No Drawing.

To allwhomc'tmay concern: a

Be it known that I, Amuan PAoz, a citizen of-the United States, residingat Cleveland Heights, in the county of Cuyahoga and State of Ohio, haveinvented a certain new and useful Improvement in Processes andComposition of Matter for Deoxidizing Metals and Alloys, of which thefollowing is a full clear, and exact description.

This lnvention relates to the production and refining of metals andalloys and has special reference to the manufacturp of steel, t ioughnot limited thereto. It is well known that one of the important effectsto be guarded against is the presence of oxygen or oxygen compounds inthe resultant metal for which reason various deoxidizers are employed,chiefly manganese, silicon, aluminum and titanium, or alloys thereof..Of these the most powerful deoxidizer is aluminum, its effect, astletern'iined by Brinell, being ninety times that of manganese andeighteen times that of silicon, but its use is attended with certainpractical ditiiculties, chief among which is the refractory nature ofthe alumina roduced and the difficulty of removing it rom the bath. As aresult the particles of alumina remain disseminated throughout the masswith serious impairment of the physical properties.

The main object of my invention is the provision of a method andcomposition of matter for the treatment of such metals and alloys .asshall enable the utilization of the (leoxidizing properties of aluminumwhile avoiding these disadvantages; the provision of a composition ofmatter containing ingredients additional to the aluminum, which underthe conditions of reaction, will combine with the alumina to produce aslag of lower melting point than the metal bath; the provision of a newand improved process for introducing alloying elements in steel andother metal baths; the provision of a process for producing alloy steelsby the use of alloying ingredients introduced in other than the metallicstate; the provision of a simple rocess and composition of matter forpro ucin alloy steels and other al- .loys free from a mixture withnon-metallic impurities; while further objects and advantages of myinvention will become apparent as the description proceeds. Thisapplication is in part a continuation of my former application filedMarch 18, 1920, Serial No. 366,968." i

Application filed May 11, 1%?21. Serial No. 468,779.

The essence of my invention consists in the admixture with thealuminun'i of a substance capable of uniting with the resultingaluminato produce an easily fusible slag. iiccordlng'to the simplestform of the invention, powdered aluminum is briquetted with cryollte orwith sodium aluminum fluoride artificially produced and introduced intothe molten bath. Another mode of producing this result resides in theemployment of substances not initially capable of uniting with aluminabut which become capable of such aption under the conditions of thereaction. I or example: I mix thoroughly and com pact into riquette formfinely divided alum num, and sodium silico-fiuoride, the aluminum beingpresent in excess of that required to replace the silicon. For example,1 take two parts of pulverized aluminum to one part of sodiumsilico-fluoride, briquette the composition with or without the use of abinder, and introduce deep into a molten bath of steel or like metal,afterwards stirring to incorporate thoroughly,or I mtroduce'a briquetteof this material into the bottom of the mould and pour the steelthereon, mixing being effected by the flowmg. The reaction is asfollows: Each 56 parts of the sodium silico-fiuoride reacts w th 11parts of aluminum as follows:

The silicon together with the remainder of the aluminum combines withany oxygen thatmay be present, either in the combined or dissolvedcondition, to produce A1 0 and S1(). These combine to ether and with thedouble fluoride produce by the other part of the reaction to form a slagwhose melting point is lower than that of the metal bath. The meltingpoint of this slag can be Va ried by varying its ingredients, a higherproportion of the double fluoride decreasing it. Also the aluminum neednot be, added in pure form but may be and in fact preferably is alloyedpreviously with suiiicient silicon to produce an easily disintegratedmaterial. I also may use silico-manganesealuminum, or numerous otheraluminum alloys suitable for each specific purpose. In

only sufiicient aluminum is employed to react upon the sodiumsilico-fluoride in which case the resulting silicon, in the nascentcondition, exercises a deondizin effect far greater than when in the usu7 form, and the slag produced has a very low melting point.

As another example of my invention the briquettes may contain partssilicon, 86 parts aluminum, 56 arts Na, Si, F When introduced into a ofmolten iron or steel which contains oxygen in solution,

either in the free or combined form, a complicated reaction resultswhereby the silicon becomes oxidized to silica, a portion of thealuminum becomes oxidized to alumina, and another portion of thealuminum combines with the sodium silico-fluoride to produce silicon andsodium-aluminum-fluoride. The silica and alumina are inde dentlextremely refractory, and even w i d n com ined they possess a meltingpoint approximately that of a very pure clay, namel about 1800 C., butthe sodium-aluminumuoride has a' melting point of only about 600 C. andin addition exercisesa vigorous dissolving action upon these othersubstances with the production of a slag-like substance which meltsbelow the temperature of the bath and is therefore very easilyeliminated.

I do not restrict myself in all cases to the use of a double fluoride orsilicon, inasmuch as by using the double fluorides of other metals I canintroduce the same into the bath in metallic form, either for scavengingpurposes or alloying purposes. For example, if it be desired tointroduce uranium into steel, a step ordinarily attended with lbegreatest difiiculty, I merely substitute or sodium silico-fluoride adouble fluoride of uranium together with at least enough aluminum todisplace the same, generally with such excess of aluminum as isnecessary to deoxidize i bath' 1 dd a1 alloymg' mgred' 1 may a so a e'ent in metallic form, for example metallic tung sten, molybdenum,chromium, etc. mixed into the briquette, since a thorough deoxidation atthe instant of adding these metals is very important to the productionof a homogeneous alloy.

I do not restrict myself to the treatment of steels or of iron groumetals since other metals and allo s can deoxidized in this way, such asnic rome, Monel metal and stelli-te. Also in its broadest aspect myinvention is not restricted to the use of aluminum but may be extendedto the treatment of steel with other oxidizable substances like siliconand titanium whose oxides are comparatively infusible and the subsequentremoval of these oxides by means of combination with a more fusiblesubstance, cially one which contains sodium and uorine.

For example my broadest claims contemplate the use of sodium fluoride,equally with silico-fluoridc, although for purposes of economy and largescale production I prefer the less expensive substance.

I have already suggested the possibility of using instead of purealuminum an alloy of the same with some other substance such as silicon.The term aluminum powder as used in my claims is intended to covereither the pure aluminum or such an alloy.

Having thus described my invention what I claim is:

1. The rocess of deoxidizing steel which contains the step of addingmetallic aluminum thereto mixed with non-metallic substance adapted tocombine with a ortion. of the same with the production 0 slag-likesubstances which melt below the melting point of the steel and dissolvesaluminum and silica.

2. The process of refining iron group metals which contains the step ofincorporating into a molten bath of the same a metallic deoxidizingagent whose oxide is comparatively infusible mixed with a non-metalliccompound containing sodium and fluorine and adapted under the conditionsof the reaction to produce a different compound of sodium which willcombine with such infusible oxide to produce a substance which is morefusible than iron.

3. The process of deoxidizing steel which contains the step of adding toa molten bath of the same is a metallic deoxidizing agent whose oxide iscomparatively infusible, in company with sodium silicmfluoride and asubstance adapted to react therewith under the temperature conditions ofthe process with the generation of a secondary substance adapted in turnto combine with such infusible oxide to produce a substance which ismore fusible than the bath.

4. In the process of deoxidizing steel by the use of aluminum, the stepof adding-to the' molten bath, in conjunction with the aluminum, acompound containing sodium and fluorine under circumstances leading tothe production of a different sodium compound which will combine withalumina.

5. The process of treating steel which contains the steps of mixingintimately together approximately five parts of sodium silicofluoridewith one part of powdered aluminum and a quantity of one or moremetallic deoxidizers such as silicon, titanium or more aluminum,briquetting such mixture, and introducing such briquettes below thesurface of the molten steel.

,6. The rocess of deoxidizing steel which contains t e steps of mixinpowdered sodium silico-fluoride with at least about one fifth of itsweight of aluminum powder, briquetting the mixture, and introducing suchbriquettes below the surface of the molten steel.

7 The process of producing alloy steel and an amount of aluminum powderat least 1 steel.

fluoride mixe sufiicient to replace such other metal, briquetting the mxture, and introducing such,

briquettes beneath the surface of the molten 8. Composition of matterfor use in the production of steel consisting essentially of the doublefluoride/of an alkali metal and a non-alkali metal mixed with at leastenough aluminum powder to replace the non-alkali metal, such mixturecompacted into briquette form.

9. Composition of matter for deoxidizing steel consistin essentially ofsodium silicowith at least about one fifth of its weight of powderedaluminum and compacted into briquettes. I 10. Composition of matter fordeoxidizing steel consisting essentially of sodium silico-fluoride mixedwith a powdered metal or alloy containing at least about one fifth itsweight of inetallic aluminum, the mixture being compacted intobriquettes.

11. The process. of refining -metals and alloys which contains the stepof incorporating in a-molten bath of the same a double fluoride, one ofwhose constituents is an alkali metal; intimately mixed withaluminumpowder.

mixture of aluminum powder and a double fluoride of which sodium is aconstituent part.

13. The process of refining metals and alloys which contains the step ofincorporating in a molten bath of the same an intimate mixture ofaluminum powder and sodium silico-fluoride.

14. The process of producing complex alloys which contains the step ofintroducing into a molten bath of one of the co1nponent metals anintimate mixture of another component metal in powdered form with finelydivided aluminum and the double fluoride with sodium of yet anothercomponent metal. the aluminum being present insuch quantity as willreplace such last named metal from its combination.

15. Composition of matter for the purpose described consistingessentially of the double fluoride of an alkali metal and a non-alkalimetal mixed with an amount of aluminum powder approximately. equivalentatomically tosuch non-alkali metal, and an additional quantity of metalwhich is to be incorporated.

16. Composition of matter for the purpose described consistingessentially of sodium silico-fluoride mixed with a quantity of aluminumpowd'cr' substantially equivalent to the silicon component thereof, andan additional quantity of high melting poin metal in a powderedcondition. I

.In testimony whereof I hereunto aflix my signature. i

ALADAR raoz.

